Select Guide Of Drain Pipe For Indoor Unit; Caution On Refrigerant Leakage - Hitachi FSG Series Service Manual

5
FIELD WORK INSTRUCTION
4
5.6.

SELECT GUIDE OF DRAIN PIPE FOR INDOOR UNIT

n Selecting Method of Drain Pipe Diameter
1. Calculation of Drain Flow Volume
Calculate from that the drain flow volume is
approximately 3 (I/hr) per 1HP of the indoor unit
nominal capacity.
For Example:
Common drain pipe for four 2HP indoor units and four
2.5HP indoor units.
Total Horse Power of
Indoor Unit
Total Drain Flow Volume
2. Select Drain Pipe from Table A and B
Horizontal Common Pipe
with Slope 1/50
Horizontal Common Pipe
with Slope 1/100
Vertical Common Pipe
Table A. Permissible Drain Flow Volume of Horizontal Vinyl
Pipe
Inner Diameter
JIS Symbol
(mm)
VP20 20
VP25 25
VP30 31
VP40 40
VP50 51
5.7.

CAUTION ON REFRIGERANT LEAKAGE

n Maximum Permissible Concentration of H(C)FC Gas
The refrigerant R407C (or R22), charged in the SET-FREE
FSG system, is an incombustible and non-toxic gas.
However, if leakage occurs and gas fills a room, it may
cause suffocation.
The maximum permissible concentration of H(C)FC gas,
R407C in air is 0.3 kg/m³ according to the refrigeration and
air conditioning facility standard (KHK S 0010) by the KHK
(High Pressure Gas Protection Association) Japan.
Therefore, some effective measure must be taken to lower
the R407C concentration in air below 0.3 kg/m³, in case of
leakage.
n Calculation of Refrigerant Concentration
1. Calculate the total quantity of refrigerant R (kg)
charged in the system connecting all the indoor units
of rooms to be air-conditioned.
2. Calculate the room Volume V (m³) of each room.
3. Calculate the refrigerant concentration C (kg/m³) of the
room according to the following equation:
R R: Total Quantity of Charged Refrigerant (kg)
V: Room Volume (m³)
— = C
V C: Refrigerant Concentration (ˆ 0.3 kg/m³)
n Countermeasure for Refrigerant Leakage According
to KHK Standard
4 ™ 2HP + 4 ™
2.5 HP=18HP
18HP ™ 3 (l/hr ™ HP) =
54 (l/hr)
VP30 for above Example
VP30 for above Example
VP30 for above Example
Permissible Flow Volume (I/hr]
Slope=1/50 Slope=1/100
39 27
70 50
125 88
247 175
472 334
NOTE
VP20 and VP25: Not Applicable to Common Pipe
VP30, 40 and 50: Applicable to Common Pipe
Table B. Permissible Drain Flow Volume of Vertical Vinyl
Pipe
Inner Diameter
JIS Symbol
(mm)
VP20 20
VP25 25
VP30 31
VP40 40
VP50 51
VP65 67
VP75 77
NOTE
VP20, 25 and 30: Not Applicable to Common Pipe
VP40, 50, 65 and 75: Applicable to Common Pipe
1/25 ~ 1/100 Down-Slope
Common Drain Piping
Connecting Pipe Shall
(Horizontal)
be Downward
The facility shall be arranged as follows referring to the
KHK standards, so that the refrigerant concentration will be
bellow 0.3 kg/m³.
1. Provide a shutterless opening which will allow fresh air
to circulate into the room.
2. Provide a doorless opening of 0.15% or more size to
the floor area.
3. Provide a Ventilator, Linked with a gas leak detector,
of 0.4 m³/min or more ventilating capacity per
Japanese Refrigeration Ton (=compressor
displacement m³/h/8.5(R22) or 9.8(R407)) of the air
conditioning system utilizing refrigerant R-22.
RAS-5FSG 2.15 ton
RAS-8FSG 3.74 ton
RAS-10FSG 4.01 ton
RAS-16FSG 5.78 ton
RAS-20FSG 7.36 ton
4. Pay a special attention to the place, such as a
basement, etc., where refrigerant can stay, since
refrigerant is heavier than air.
Permissible Flow Volume (I/hr]
220
410
730
1400
2760
5710
8280
Common Drain Piping
(Vertical)
RAS-5FS3 2.48 ton
RAS-8FS3 4.31 ton
RAS-10FS3 4.63 ton
RAS-16FS3 6.66 ton
RAS-20FS3 8.49 ton